I've got a camera that when the battery dies mid-stroke, you have to put in a new one and dial the shutter speed to "B" before it will recycle. No idea if that might be helpful with a canon, but throwing it out there just in case. Good luck.

"To a photographer the world consists of an infinite number of vantage points -- places to stand -- of which very few are altogether satisfactory." (John Szarkowski, Atget)